PURPOSE: To display an LED, if it is detected that the battery capacity is scanty at the time when a key input operation is executed, when a driving battery become a low voltage, and is in a voltage state being insufficient for driving a device.

CONSTITUTION: This battery-driven type electronic apparatus is provided with an input means 3, a RAM 2 in which inputted data is stored, a ROM 1, a central processing unit 4, a system battery for driving this electronic apparatus, a backup battery 6 for assisting this system battery 8, and a low voltage detecting circuit 7 for detecting the battery capacity of these batteries. Also, this electronic apparatus is constituted of an LED flickering signal generating circuit 9 for flickering an LED at the time when a voltage value is below a prescribed value, and the LED 10, and when it is detected that the battery capacity is scanty at the time when a key input operation is executed, the LED 10 is displayed, therefore, the service life of the battery can be extended.